The Reproductive Status Core will be responsible for the collection of biological samples from women, chimpanzees, and rhesus monkeys to confirm classification of reproductive age, characterize gonadal steroid patterns within cycles, and assess menopausal status. Using previously validated immunoassays, reproductive hormone assessments will be made by Core personnel using the facilities provided by the Yerkes NPRC Endocrine Core Laboratory. Data will be transmitted to the Administrative Core and Project Leaders to schedule the cognitive testing in Projects 1 and 2 and neuroimaging in Project 3 for the early to mid follicular phase for pre- menopausal females and to quantify the gonadal hormone milieu at the time of the assessment for pre- and post menopausal females. An ovulatory cycle will be confirmed in young and middle aged females by a sustained, 7 to 10 day rise in progestin (serum progesterone for monkeys; urinary pregnanediol for chimpanzees; salivary progesterone for women). Short luteal phase ovulatory cycles will be identified by cycles with an abbreviated, 3 to 7 day, increase in progestins. The period of the sustained increase in progestins followed by menstruation will define the luteal phase. Anovulatory cycles will be identified by intermittent increases in estrogen (serum estradiol for monkeys; urinary conjugated estrogens for chimpanzees; salivary estradiol for women) in the face of persistently low and unvarying concentrations of progestins during the inter-menstrual period. The follicular phase of an ovulatory cycle will be identified as the period following menstruation characterized by rising concentrations of estrogen prior to the increase in progestin at ovulation. Menopausal status will be confirmed in aged rhesus monkeys by elevated serum levels of FSH in the face of reduced estradiol and inhibin B concentrations; persistently low and unvarying serum progesterone; and amenorrhea in rhesus monkeys; in aged chimpanzees by elevated urinary of FSH in the face of reduced conjugated estrogen; persistently low pregnanediol concentrations; amenorrhea; and reduced perineal swellings; and in older women by reduced salivary concentrations of estradiol and progesterone in the face of amenorrhea and self-reports of menopausal symptoms.